Trying my best to keep an open mind, I set off in search of a hidden being. Hafnarfjördur, a suburb of Reykjavik and renowned for having one of Iceland's largest colonies of elves and spirit beings, seems like a good place to start. My guide is Sibba, a middle-aged woman in a red elf hat. She tells me that visitors sometimes spot supernatural beings on her tours.

We walk through a typical Icelandic neighborhood of corrugated-iron houses huddled by the harbor. Sibba points out some rocks beside a driveway that are thought to be the home of a dwarf. She tells me that, years ago, a local man tried to pry them open with a metal spike, which snapped in two. Half of it remains lodged in the rock face, like King Arthur's sword in the stone.

I pull on the rusted spike, but it refuses to budge. We stand beside the rocks in a reverential hush, listening for I'm not sure what. There is no sound apart from the sighing of the wind.

Our next stop is a small park in the middle of a 7,500-year-old lava field. Sibba steers me toward a black boulder believed to be the home of another dwarf. He recently made himself visible to a tourist, she says, and complained to her about the noise in the park.

I knock on the boulder and listen. Then I ask the dwarf to show himself, or at least give us a sign. Again, nothing. "Maybe he is out," Sibba whispers.

Not everyone in Iceland believes in the elves and hidden people. Many think they do not exist at all, or that they are no more than an amusing bit of folklore or symbols of Mother Nature.

Even true believers cannot agree on how to interact with them. Erla Stefánsdóttir, Iceland's most famous psychic, sees hidden beings everywhere she goes, from her backyard to the parking lot at the local supermarket. Although she has published maps of their homes, she disapproves of guided tours.

"It is too much fuss," she says. "People should connect with nature by going into it and meditating rather than running around pointing at rocks and trying to see elves."

Maybe so, but a visit to Iceland somehow seems incomplete without at least one brush with the supernatural. To my relief, and astonishment, something straight out of The Twilight Zone happens to me on my final day.

The search for a last-minute souvenir takes me to an artists' cooperative housed inside an old fishnet factory in Reykjavik. It is a weekday, and the building is quiet. Eventually, a young man appears, smoking a cigarette, and suggests that I take a little tour.

I wander alone through a maze of half-lit corridors. Some of the rooms are empty. Others contain upturned furniture, scraps of wood, and curtains hanging from the ceiling. It could be a haunted house from central casting.

In the basement, things turn genuinely spooky. I feel that someone is watching me. I call out but nobody answers. A shiver trickles through me. I decide to leave, walking at first, then quickening the pace. By the time I reach the stairs, I'm running.

Smoking Man is waiting at the top, smiling triumphantly. "I see you met our ghost," he says. "Everyone here has felt his presence. He gets irritated and scares people."

I nod meekly. Anywhere else in the world, this would have been a cue to laugh or say something wry and skeptical. But the normal rules do not apply in Iceland, nor to its people - hidden or otherwise.